Double acting torque wrench



Dec. 15; 1970 H. A. THOMASIAN DOUBLE ACTING TORQUE WRENCH Filed May 16, 1968 2 Sheets-Sheet 1 INVENTOR. HARVEY A. THOMASIAN ATTQRN Y Dec. 15, 1970 H. A. THOMASIAN DOUBLE ACTING TORQUEWRENCH 2 Sheets-Sheet 2 Filed May 16, 1968 FIG.3

FIG.4

United States Patent O US. Cl. 73139 4 Claims ABSTRACT OF THE DISCLOSURE A torque wrench comprising a torque bar having one end secured to a square terminal adapted to engage a wrench socket while the other end is engaged by a transversely positioned coiled spring, a combined pointer and electric wiper contact pivotally mounted on a vertical shaft the lower end of which carries a small gear, a pivotally mounted gear sector meshing with said small gear and provided with a radial slot, a stud carried by the torque bar and projecting upwardly therefrom and into the slot to swing the gear sector and rotate the vertical shaft and the pointer when the torque bar swings in one direction, a metal sector pivotally mounted on a vertical axis and manually adjustable to different positlons so that it can be contacted by the end of the pointer at a predetermined torque, a handle at the rear end of the wrench containing a dry battery, a sound producer positioned in front of the pointer, and electric connections for operating the sound producer by energy from the battery when the end of the pointer moves into contact with the metal sector.

BACKGROUND OF THE INVENTION The field of the invention is measuring and testing with a torque wrench having signal operating means.

The state of the prior art is set forth in US. Pats. 2,682,796 and 2,792,734 of Larson et al. Larson et al. set forth the problems encountered in the use of a torque Wrench wherein the wrench is used in a restricted area or a noisy area and it is impossible to view the indicator dial or distinguish a signal from the background noise. The answer of Larson et al. to the prior art problems was a torque wrench having a bell actuated by the degree of twist deformation in a shank or shaft. In the prior art devices no dial indicator was provided for visual inspection.

SUMMARY OF THE INVENTION Having in mind the limitations of the prior art, it is an object of the present invention to provide a torque wrench having audible and visual sensing means incorporated therein.

Another object of the present invention is to provide a torque wrench which incorporates an audible sensing means which includes a speaker, an oscillator and an amplifier.

According to the present invention, a double acting torque wrench is provided which gives an audible signal whenever a predetermined torque is exerted in either direction, the value of such predetermined torque being adjustable and readable on a scale on the top of the wrench.

DESCRIPTION OF THE DRAWING AND THE PREFERRED EMBODIMENTS A preferred embodiment of the invention is shown on the drawing wherein:

FIG. 1 is a plan view of the wrench with portions broken away;

FIG. 2 is a longitudinal cross section of the wrench with a portion broken away;

3,546,932 Patented Dec. 15, 1970 FIG. 3 is a bottom view in longitudinal section of the rear portion of the wrench; and

FIG. 4 is a schematic diagram, partly in cross section, showing the wiring diagram.

Referring particularly to FIGS. 1 and 2, a double acting torque wrench is shown comprising a housing section 1 and a cover plate 2, 2'. The torque indicating and signalling mechanism is carried by the cover plate which is secured to the housing by a front screw 3, rear screw 4 and additional screws 5 near the middle of the wrench.

The front end of the wrench is equipped with the usual square terminal 6 to engage a socket or other turning device and a torque bar 7 is centrally positioned in the housing between two identical coiled springs 8 serving to transmit the applied torque to the front end of the wrench. The torque bar can 'be formed intergral with the terminal 6, or it can be in the form of a closed-end wrench with a square hole, a cotter pin 6' being used to keep it connected to the square terminal 6.

The enlarged middle portion of the cover plate has mounted on it a housing 9 for a combined pointer 10 and an electric wiper contact 11 to be moved into engagement with one or the other of two pivoted sectors 12 to close an electric circuit to operate a speaker, buzzer or other noisemaking device 13 when a predetermined torque is reached. An amplifier and oscillator 14 is provided for converting the electric current from the battery 15 into signals that are suitable for operating the sounder 13. The periphery of the housing 9 is provided with numerical indicia to indicate the torque in each position of the pointer 10, the edges of the wiper contact 10 and sectors 12 being rounded and the middle portion of the pointer 10 being thin and flexible to permit the pointer to ride easily upon the sectors.

As particularly shown in FIG. 4, pointer 10 is firmly secured to the upper end of a pivot shaft 16 and carries a disk 17 of electric insulation material to prevent accidental metallic contact of the pointer with the sectors 12. The shaft 16 is rotatably mounted in a central borehole in a block 18 of insulation material and also passes through aligned bearing holes in plates 19 and 20 of insulation material. The lower end of shaft 16 has firmly secured to it a small gear 211 driven by a gear sector 22 (FIG. 3) pivotally mounted at 23 (FIG. 2) and provided with a radial slot to receive a stud 24 projecting upwardly from the torque bar 7. The middle and slotted portions of the gear sector 22 should be made of insulation material, but the small gear 21, which should be of metal, should have a radial arm 25 and coiled spring connected to it to serve not only to take up any backlash from the gearing in either direction, but also to provide a return path for the electric current from the battery.

With particular reference to FIG. 4, each of the two sectors 12 is shown firmly secured to the upper end of a pivot shaft 26 rotatably mounted in a borehole in the circular block 18 and in aligned holes in insulation plates 19 and 20, each pivot shaft 26 carrying a toothed gear 27 at its lower end. The two gears 27 (FIG. 3) mesh With each other and are also in mesh respectively with the rightand left-hand screw threads of a transverse shaft 28 journalled in the cheek portions 2' (FIG. 2) of the cover plate and carrying knurled knobs at its free ends. By rotating this shaft in one directon or the other, the two sectors can be moved forward or backward in unison to adjust and indicate the torque at which the sounder will respond. Obviously the mechanism would still be operative, although not with the same degree of precision, if only one of the screw threaded portions were used.

It will be understood that this invention is susceptible to modification in order to adapt it to different usages and conditions and, accordingly, it is desired to compresocket element, the handle being hollow and having hend such modifications within this invention as may fall a battery contained therein; and within the scope of the appended claims. (i) a sound producer mounted in the housing and con- Iclaim: nected electrically with the battery when the end 1. A torque wrench comprising: of the pointer contacts a metal sector. (a) an elongated housing; 2. A torque wrench as recited in claim 1, wherein the (b) a torque bar pivotally mounted in the housing and two metal sectors are supported respectively on two having one end secured to a socket element, while the spaced parallel pivot shafts. other end is normally centered in the housin by 3. A torque wrench as recited in claim 2, wherein the transversely positioned coiled spring; parallel pivot shafts carry intermeshing gears at their (0) a combined pointer and electrical wiper contact lower end.

pivotally mounted in the housing on a vertical shaft, 4. A torque wrench as recited in claim 3, wherein the the lower end of which carries a small gear; intermeshing gears are rotated respectively by right hand ((1) a pivotally mounted gear sector meshing with said and left hand threads on a single transverse shaft.

small gear and provided with a radial slot; (e) a stud carried by the other end of the torque bar References Cited and projecting upwardly therefrom into the slot to UNI ED STATES A N S zj f f iii iffiig g ff 31x32? Shaft 2,225,420 12/1940 Mandl 77-139 (f) two mgtal sectors pivotally r nounted in the housing 2792734 5/1957 Larson 73 139 2,877,645 3/1959 Nealey 73139 in side-by-side relationship, the sectors being manually adjustable to different positions so that one of FOREIGN PATENTS said sectors is contacted by the end of the pointer 325 12/1959 Great Britain 61 1W4 at a selected clockwise torque and the other of said sectors contacted at a selected counterclockwise RICHARD C, QUEISSER, Primary Examiner torque; (g) a single means for simultaneously adjusting the US. Cl. X.R.

position of both of said sectors; 240-266; 8152.5 (h) a handle at the end of the housing opposite the 

